To prevent microbial spoilage, a hot fill process is often used to package many food and beverage products at high temperatures to sterilize both the product and the container. When the liquid content of the container cools, it contracts and either creates an internal vacuum or causes the container to deform, as by shrinking, buckling or paneling. Currently, plastic bottles are designed with panels, ribs and additional resin to compensate for the contraction and prevent bottle deformation. When the smooth side wall of the bottle is replaced with these panels, flexible packaging shapes and designs are prevented, thereby making label application difficult.
An approach to the bottle deformation problem adds a gas, such as carbon dioxide or liquid nitrogen to the bottle after the liquid is hot-filled and before sealing. This approach is described in U.S. Pat. Nos. 4,662,154, 5,033,254 and 5,251,424 and in German Offenlegungsschrift No. DE 40 36 421 A 1. For example, the process described in U.S. Pat. No. 5,251,424 introduces liquid nitrogen into the bottle before sealing to prevent thermal distortion of the bottle upon cooling of the hot liquid.
After closing, the gas expands within the headspace and the pressure inside the container rises rapidly providing rigidity to the container. This operation is most effective when applied to cold filled plastic containers that can accept relatively high pressures without stretching and deforming. At hot fill temperatures however, the container looses its design strength. This loss of strength allows the container to stretch and deform, making it impossible to pressurize the container to the same pressure levels that can be achieved with cold fill operations.
Another approach to the bottle deformation problem adds a carbon dioxide releasing device to the container before sealing. This approach is described in U.S. Pat. Nos. 5,270,069 and 6,244,022. For example, the device described in U.S. Pat. No. 5,270,069 comprises a pencil shaped device that includes two compartments in which are disposed different reagents that, when brought into contact, react to release carbon dioxide into the headspace of the bottle. The user must remove the device before consuming the beverage.
Packaged beverages that contain a carbonation device that is activated at the point of consumption to carbonate the beverage are described in U.S. Pat. Nos. 3,888,998, 4,007,134, 4,110,255, 4,186,215, 4,316,409, 4,458,584, 4,475,448, 4,466,342 and in British Patent Application GB 2 076 628 A. Sieve tablets used in many of these devices are described in U.S. Pat. Nos. 3,888,998, 4,007,134, 4,110,255 as well as in U.S. Pat. Nos. 4,025,655 and 4,214,011. These sieve tablets leave a residue that must be removed, from the beverage prior to consumption.
In a hot fill process, the food and beverage products are pasteurized and then filled into containers at high temperature. The entire heating and cooling cycle can take a significant amount of time meaning that the actual food or beverage components are exposed to high temperatures for extended periods of time. During this time, certain components referred to as “Heat Sensitive Components” can become degraded by the high temperatures and lose their true aromatic and flavor characteristics.
Thus there is a need for a method that releases gas in a closed container to retain microbial stability without leaving a residue or a device that must be removed at time of consumption.
There is also a need to eliminate buckling or paneling in closed hot filled containers in order to capture decorative, lightweight and flexibility benefits.
There is also a need to sufficiently pressurize a closed hot filled container in order to capture structural benefits without deforming the container.
There is a further need to release ingredients and functional components to closed containers on a time delayed basis to enhance functionality.
There is still another need for a container in which gas can be released to pressurize the container after the container is sealed.
There is yet another need for a closure or cap for a container that can release gas into the container after sealing to pressurize the container.